vtkWin32Header: always use {Get,Set}WindowLongPtr
vtkWin32Header: always use {Get,Set}WindowLongPtr

These have been in mingw since 2011.

Change-Id: I35cede39029bb18a6fa7dc1d9f27db914e3d763b

demarle/VTK,hendradarwin/VTK,johnkit/vtk-dev,jmerkow/VTK,ashray/VTK-EVM,demarle/VTK,demarle/VTK,SimVascular/VTK,sankhesh/VTK,hendradarwin/VTK,sumedhasingla/VTK,gram526/VTK,demarle/VTK,SimVascular/VTK,keithroe/vtkoptix,mspark93/VTK,sankhesh/VTK,candy7393/VTK,msmolens/VTK,msmolens/VTK,SimVascular/VTK,johnkit/vtk-dev,hendradarwin/VTK,candy7393/VTK,gram526/VTK,mspark93/VTK,mspark93/VTK,SimVascular/VTK,SimVascular/VTK,sumedhasingla/VTK,mspark93/VTK,mspark93/VTK,sumedhasingla/VTK,gram526/VTK,keithroe/vtkoptix,jmerkow/VTK,sumedhasingla/VTK,sankhesh/VTK,demarle/VTK,sankhesh/VTK,gram526/VTK,msmolens/VTK,ashray/VTK-EVM,keithroe/vtkoptix,hendradarwin/VTK,johnkit/vtk-dev,candy7393/VTK,jmerkow/VTK,gram526/VTK,mspark93/VTK,ashray/VTK-EVM,jmerkow/VTK,sumedhasingla/VTK,SimVascular/VTK,SimVascular/VTK,demarle/VTK,msmolens/VTK,jmerkow/VTK,keithroe/vtkoptix,johnkit/vtk-dev,mspark93/VTK,gram526/VTK,johnkit/vtk-dev,hendradarwin/VTK,demarle/VTK,jmerkow/VTK,candy7393/VTK,mspark93/VTK,hendradarwin/VTK,sumedhasingla/VTK,keithroe/vtkoptix,ashray/VTK-EVM,candy7393/VTK,ashray/VTK-EVM,gram526/VTK,SimVascular/VTK,jmerkow/VTK,gram526/VTK,msmolens/VTK,keithroe/vtkoptix,sumedhasingla/VTK,sankhesh/VTK,msmolens/VTK,sankhesh/VTK,msmolens/VTK,ashray/VTK-EVM,candy7393/VTK,msmolens/VTK,demarle/VTK,candy7393/VTK,keithroe/vtkoptix,sankhesh/VTK,candy7393/VTK,sankhesh/VTK,jmerkow/VTK,johnkit/vtk-dev,sumedhasingla/VTK,hendradarwin/VTK,ashray/VTK-EVM,johnkit/vtk-dev,keithroe/vtkoptix,ashray/VTK-EVM